This STTR Phase II application is to finalize the one-of-its-kind Assessment of Liability and Exposure to Substance use and antisocial behavior(c) (ALEXSA(c)) for educator, pediatric, prevention and epidemiology uses. The ALEXSA system, first funded by a NIDA K-Award, acquires child-report (8- to 13-year-olds) data using an illustrated, computer format that is enjoyable and can be completed by illiterate youth. Nine risk domains (factor scores) and over 40 risk factor subscales canbeusedtomeasure liability to, and early forms of, problematic substance use (SU) and chronic behavior problems. The ALEXSA can be administered by child care professionals to groups of children or individuals. It is unique among child-report assessments in developmental appropriateness, breadth of characteristics measured, flexibility for tailored assessment, user-friendliness, and utility for research and intervention. The ALEXSA offers customers a format perceived by youth to have greater confidentiality than paper forms, automated data storage, and scores immediately upon completion (e.g., for screening and referral to intervention). Among ALEXSA's psychometric properties is a brief screen with an overall 85% predictive accuracy of SU one-year later among high-risk youth younger than 12 years old. This screen thus detects youth at high risk for substance use disorder long before its onset providing long-term opportunity for prevention. Phase I work developed a highly portable net book version and a PDA screen version of the ALEXSA. Phase II efforts will refine the ALEXSA using sophisticated methods and an extensive evaluation to enable in-depth clinical assessment of individuals (akin to IQ tests). ALEXSA scoring will be standardized to the U.S. general population. ALEXSA system products will be tailored to the needs of specific professions based on expert reviews. User's Manuals will be created. All products will be refined to be publish-quality. Collectively, this augmentation of the innovative ALEXSA research instrument into a tool that provides state-of-the-art assessment will assist professionalism meeting mandates for 6 million annual early intervention services and SU/SUD risk screenings by over 93,000 behavioral health professionals, over 150,000 primary care physicians and 41,000 school psychologists. The ALEXSA's innovative features, broad and evidence-based subscales and scores, and psychometric properties will permit it to fill gaps in several large niche markets and create barriers to potential competitors.